Preparation of basic polyvalent metal salts of organic acids



United States Patent PREPARATION OF BASIC POLYVALENT METAL SALTS OF ORGANIC ACIDS Grant E. Warren, deceased, late of Martinez, Calif., by Eleanore R. Warren, executrix, Martinez, Califi, Henry W. Anderson, Houston, lex., and Hyman Rather, Berkeley, Calif., assignors to Shell Development Company, New York, N. Y., a corporation of Delaware No Drawing. Application February 6, 1957 Serial No. 638,478

19 Claims. (Cl. 252-33) This invention relates to a method for preparing basic polyvalent metal salts of oil-soluble organic acids, particularly of oil-soluble petroleum sulfonic acids. More specifically, it relates to the preparation of mineral oil solutions of highly basic alkaline earth metal petroleum sulfonates.

It is well known that when preparing a salt or soap of an organic acid, the mere use of an excess of neutralizing agent, generally the oxide, hydroxide, carbonate, etc., of the desired metal, may result in a product which contains an amount of metal in excess of that theoretically required to replace the acidic hydrogens of the organic acid used as the starting material. For many uses, particularly as addition, agents for lubricants, desirable results are obtained by the use of these so-called basic salts or soaps. The alkalinity of these products, in addition to improving the detergent properties of the oil, imparts the further characteristic of increasing What has been called the alkaline reserve of the oil. Alkalinity of lubricating oils is of interest for decreasing wear of piston rings and cylinders. This is believed to be accomplished by neutralization of sulfur acids formed from combustion of the fuel, which otherwise result in corrosive wear.

With the demonstrated superiority of such basic soaps over the normal or slightly acidic soaps, many attempts have been made to increase thebasicity of the salts or soaps. Generally, the prior art processes involve the use of a large excess of neutralizing agent in a process more or less conventional for producing salts or soaps. As a result of the prior work in this field, it has been found that there is a definite upper limit to the amount of basic material which can be held in combination in these products. For example, the preparation of basic calcium mahogany sulfonates by conventional processes results in a product having a control'ratio of not more than about 2.5, that is, about .44 mole of basic material per mole of neutral calcium petroleum sulfonates. The control ratio is defined as follows:

Control ratio alkalinity (mg. (KOH/g. concentrate) percent sulfate ash In the above expression and as used throughout the pres ent specification, the term alkalinity means total base number determined by electrometric titration according to ASTM designation D664-49. By this test, meta1hydroxides, such as Ca(OH) and weak salts of the same metals, such as CaCO have equal alkalinity on a molefor-mole basis. Sulfate ash is determined by first igniting the sample until only ash and carbon remain, then heating with sulfuric acid at 500 F. until carbon is oxidized, cooling, reheating with sulfuric acid, and then igniting to "775 F; This test, the official name of which is Sulfated Residue, is detailed in ASTM D874-47T. It is a principal object of the present invention to provide an improved process for the preparation of basic salts of oil-soluble organic acids A more specific obice ject is to provide animproved process for the preparation of oil-soluble, basic polyvalent metal, especially alkaline earth metal, petroleum sulfonates. Still another object is to provide an improved process for the preparation of mineral oil solutions of oil-soluble basic alkaline earth metal petroleum sulfonates. Other objects and advantages will become apparent from the detailed description of the invention.

By means of the present invention, it is now possible to obtain basic polyvalent metal salts of oil-soluble organic acids which are more basic and have higher control ratios than is possible by conventional processes.

It has now been found that highly basic. polyvalent metal salts of oil-soluble organic acids can be prepared by a process comprising reacting an oil-soluble organic acid compound with a polyvalent metal carbonate which is formed in situ.

More particularly, the process of the present invention comprises reacting, in the presence of a substantial amount of water, an oil-soluble organic acid compound, for example, an organic sulfonic acid compound, with a polyvalent metal carbonate which is formed in situ.

Still more specifically, the present process comprises reacting, in the presence of a substantial amount of water, an oil-soluble organic acid compound, preferably a petroleum sulfonic acid compound, with a polyvalent metal salt, preferably an alkaline earth metal salt, of carbonic acid, which salt is formed in situ from the reaction of a polyvalent metal base and carbon dioxide, at least a portion of the polyvalent metal base which reacts with the carbon dioxide being in its free state, that is, in its non-complexed state.

According to a preferred embodiment, a mineral oil solution of oil-soluble, highly basic alkaline earth metal, such as calcium, petroleum sulfonates, is prepared by a process comprising admixing with a mineral oil solution of an oil-soluble petroleum sulfonic acid compound, a. substantial proportion of water and a substantial proportion of an alkaline earth metal base, and adding carbon dioxide to the resulting admixture.

Described in greater detail with specific reference to the preparation of a mineral oil solution of oil-soluble highly basic alkaline earth metal sulfonates from a mineral oil solution of oil-soluble neutral or slightly basic alkaline earth metal sulfonates, the present process comprises admixing, at an elevated temperature, for example, at a temperature of from about F. to about 250 F., preferably from about 180 F. to 210 F., a mineral oil solution containing from about 10% to about 50%, and preferably from about 15% to about 40%, by weight, of oil-soluble neutral or slightly basic alkaline earth metal sulfonates with an alkaline earth metal base and with at least 2%, and preferably at least 5%, by Weight, based on the oil-sulfonate starting material, of Water; adding carbon dioxide to the resulting admixture, the amount of carbon dioxide added being preferably less than the theoretical amount required to convert the added alkaline earth metal base to the corresponding alkaline earth metal carbonate; drying the resulting product, as by heating to temperatures of the order of 280-320 R, and filtering the dried product to remove suspended solids, such as excess alkaline earth metal base. It is preferred to add the carbon dioxide gradually to the reaction mixture, the feed rate being dependent on the type of equipment employed. The carbon dioxide can be added to the reaction mixture, for example, by bubbling it through the reaction mixture or by introducing the reaction mixture into an atmosphere of carbon dioxide, Preferably, the reaction mixture is agitated vigorously during the addition of the carbon dioxide.

It is to be understood that the term organic acid com: pound includes the free organic acid as well as the salts thereof, particularly the alkali metal salts and the alkaline earth metal salts thereof. When employing the free organic acid or the alkali metal salt thereof as the starting material for the preparation of highly basic polyvalent metal salts according to the present invention, any condition necessary for the formation of the neutral polyvalent metal salt must also be met. For example, in the preparation of highly basic calcium petroleum sulfonates from sodium petroleum sulfonate in a one-stage operation, a water-soluble calcium salt, such as calcium chloride, should be added to the reaction mixture since the Watersoluble calcium salt is necessary in the formation of the neutral calcium petroleum sulfonate.

The variety of classes of oil-soluble organic acids which can be employed in the practice of the present invention are, .for example, sulfur acids and carboxylic acids of the aliphatic and cyclic types, and the corresponding thioacids.

The sulfur acid compounds which can be used include sulfonic, sulfarnic, sulfinic, thiosulfonic, etc., acid compounds. Of these, the sulfonic acid compounds find par ticular application under the present invention. The sulfonic acids (or salts thereof) which can be employed include the aliphatic-substituted cyclic sulfonic acids in which the aliphatic substituent or substituents contain a total of at least 12 carbon atoms, for example, alkylaryl sulfonic acids, alkylcycloaliphatic sufonic acids, and alkyl-heterocyclic sulfonic acids, and aliphatic sulfonic acids in which the aliphatic radical contains at least 12 carbon atoms, particularly long chain aliphatic sulfonic acids. Specific examples of oil-soluble sulfonic acid compounds which can be used include: petroleum sulfonic acids; petrolatum sulfonic acids; monoand polywax substituted naphthalene sulfonic, phenol sulfonic, diphenyl ether sulfonic, diphenyl ether disulfonic, naphthalene disulfide sulfonic, naphthalene disulfide disulfonic, diphenyl amine disulfonic, diphenyl amine sulfonic, thiophene sulfonic, alpha-chloronaphthalene sulfonic acids, etc.; other substituted sulfonic acids such as cetylchlorobenzene sulfonic acids, cetylphenol sulfonic acids, cetylphenol disulfide sulfonic acids, cetylphenol monosulfide sulfonic acids, cetoxy capryl-benzene sulfonic acids, dicetyl thianthrene sulfonic acids, dilaurylbeta-naphthol sulfonic acids, and dicaprylnitronaphthalene sulfonic acids; aliphatic sulfonic acids such as parafiin wax sulfonic acids, unsaturated paraffin wax sulfonic acids, hydroxy substituted paraffin wax sulfonic acids, tetraisobutylene sulfonic acids, tetraamylene sulfonic acids, chloro-substituted paraffin wax sulfonic acids, nitroso paraflin wax sulfonic acids, etc.; cycloaliphatic sulfonic acids, such as petroleum naphthene sulfonic acids, cetylcyclopentyl sulfonic acids, laurylcyclohexyl sulfonic acids, bis-(diisobutyl)-cyclohexyl sulfonic acids, monoand poly-wax substituted cyclohexyl sulfonic acids, etc; and salts of the foregoing.

The term petroleum sulfonic acids is intended to cover all sulfonic acids which are derived directly from petroleum products.

, The carboxylic acids which can be employed are the oilsoluble carbocyclic carboxylic acids, including those containing a benzenoid structure, i. e., benzene, naphthalene, etc., and an oil-solubilizing radical or radicals having a total of at least about 12 carbon atoms. Such acids are the oil-soluble aliphatic substituted aromatic acids as, for example, stearylbenzoic acids, monoor polywax substituted benzoic or naphthoic acids, and particularly the long chain alkyl salicyclic acids. The carbocyclic carboxylic acids also include cycloaliphatic carboxylic acids containing at least about 12 carbon atoms. Examples of such acids are the petroleum naphthenic acids, cetylcyclohexane carboxylic acids, di-lauryl decahydronaphthalene carboxylic acids, di-octylcyclopentane carboxylic acids, etc. It is also contemplated to employ the thio-carboxylic acids, that is, those carboxylic acids set out above in which one or both of the oxygen atoms of the carboxylic group are replaced by sulfur. Salts of the foregoing acids can also be used.

Of the various types of oil-soluble organic acids which can be used, it is preferred to employ as the starting material, the oil-soluble organic sulfonic acid compounds. The present invention is particularly applicable to the preparation of mineral oil solutions of oil-soluble, highly basic alkaline earth metal petroleum sulfonates from mineral oil solutions of sulfonic acid compounds obtained by sulfonating petroleum hydrocarbon material, particularly petroleum lubricating oil fractions. Sulfonation of the petroleum hydrocarbon material with subsequent neutralization of the free sulfonic acids with an alkali metal hydroxide, can be effected by any known method as described, for example, in the following U. S. patents: 1,901,383; 2,285,390; 2,462,829; 2,514,733; 2,523,582 and 2,578,657. The resulting mineral oil solution of alkali metal petroleum sulfonates, preferably after concentration and purification, for example, by extraction with a low molecular weight alcohol or ketone, such as tert.-buty1alcohol, can be used as the starting material for the process of the present invention. However, it is preferred to convert the mineral oil solution of alkali metal petroleum sulfonates to a mineral oil solution of neutral or slightly basic alkaline earth metal petroleum sulfonates by any conventional method, and employ the resulting material as the starting material for the purposes of the present invention.

It is preferred to dissolve the oil-soluble organic acid compound in a suitable hydrocarbon prior to conversion thereof to the highly basic polyvalent metal salt. Preferred hydrocarbon solvents are mineral oil fractions having a relatively low viscosity so that subsequent filtration of the highly basic product is facilitated, and having also relatively low volatility, mainly for the reason that the resulting mineral oil concentrate of the highly basic product is generally used as an additive for lubricating oil compositions. Any lubricating oil fraction can be used. Lubricating oil fractions having a viscosity of from about to about 400 seconds Saybolt Universal at 100 F. are most suitable. The concentration of the oil-soluble organic acid compound in the mineral oil solution is generally "from about 10% to about 50%, and preferably from 15% to about 40%, by weight.

The polyvalent metal carbonate which is employed as the basification agent in the present invention, is formed in situ, generally by the reaction of a polyvalent metal base, preferably an oxide or hydroxide of an alkaline earth metal, i. e., calcium, barium, strontium, or magnesium, and carbon dioxide. Preferably, the polyvalent metal base is admixed with the oil-soluble organic acid compound, and carbon dioxide is then added to the re sulting admixture, preferably with vigorous agitation. The amount of polyvalent metal base added depends on the basicity desired in the final product. In cases where the free organic acid or alkali metal salt thereof is employed as the starting material, the amount of polyvalent metal base should be in excess of that required to form the neutral polyvalent salt of the organic acid compound. Since the present invention is intended principally to provide a process for the preparation of basic polyvalent metal salts of the organic acids which salts are more basic than those formed merely by heating the organic acid compound with an excess ofpolyvalent metal neutralizing agent, the amount of polyvalent metal base employed in the present process should exceed that which will normally react or complex with an organic acid compound merely by heating the organic acid compound with an excess of such polyvalent metal base, which amount varies depending upon the particular organic acid compound employed. Thus, in the present process, at least a portion of the polyvalent metal base which reacts in situ with the weak inorganic acid should be in its free state, that is, in its unreacted or non-complexed state. The amount of polyvalent metal base used should contain at least two equivalents of polyvalent metal toreach 'equivalent of organic acid anion. The amount of base added is usually substantially higher than that desired in the product since not all of the added base is necessarily solubilized in the oil phase.

The amount of carbon dioxide employed preferably should not exceed the theoretical amount required to convert the added polyvalent metal base to the polyvalent metal carbonate. Preferably, at least one mole of carbon dioxide per two equivalents of organic acid anion is used.

The amount of water present in the reaction mixture should be at least about 2% by weight, for example, from about 5% to about 50% by weight, based on the oilsoluble organic acid compound starting material or, where an oil solution thereof is employed on the weight of the oil solution. The water and the polyvalent metal base can be separately added to the organic acid compound starting material, or an aqueous suspension of the polyvalent metal base can be prepared and this suspension then added to the organic acid compound starting material. When utilizing an aqueous suspension or slurry of the polyvalent metal base, the concentration of the base in the suspension is usually from about to about 60%, and preferably from about to about by weight. In the case of separate additions of water and polyvalent metal base, the weight ratio of base to water can be as high as 9, but is preferably from about /2 to about 4.

The temperature at which the present process is conducted is generally between about 150 and 250 F., preferably between about 180 F. and 210 F. When the process is carried out under atmospheric pressure, the temperature should not exceed about 210 F., and preferably not exceed about 200 F. so that the water present in the reaction mixture is not completely removed before the basification reaction is complete. By carrying out the process at pressures higher than atmospheric, temperatures of as high as 250 F. can be employed. 'When the reaction product has reached the desired basicity, the reaction mixture is dried, as by heating to temperatures of 280-320 F. If desired, the dried product can be airblown. The dried product is then filtered to remove suspended solids.

The exact nature of the highly basic products prepared by the present process has not yet been fullydetermined. It is believed that the basicity of the final product is due mainly tothe presence therein of the polyvalent metal carbonate used in the basification reaction and, to a minor extent, to. the presence of the polyvalent metal base.

The following examples are illustrative of the present invention, and are not to be considered as limiting the specification or claims in any manner:

Example I 140 grams of a mineral oil solution containing about 33 by weight of calcium petroleum mahogany sulfonates and having-a base number (mg. KOH/g. concentrate) of about 20 and a control ratio of about 2.5, was diluted with 140 grams of a lubricating oil fraction having a viscosity of about 400 SSU (Seconds Saybolt Universal) at 100 F. The base number of the diluted solution was about 10. The resulting dilute solution was admixed with 8.8 grams of calcium hydroxide which was slurried in 24 cc. of water. The admixture was heated to 200 F. and maintained at this temperature during subsequent addition of carbon dioxide. Carbon dioxide was introduced into the admixture, with rapid stirring, at a rate of 5.6 cc./sec. for 35 minutes. The resulting product was dried by heating to 300 F. and the dried, hot product was filtered. The product has a base number of 40.9, a control ratio of 5.28 and an equivalent base ratio (EBR) of 178. The equivalent base ratio is defined as:

When the above procedure was carried out omitting .6 I carbon dioxide, the base number of the res'ultin'g product was still 10, indicating no increase-in the basicity' of the starting material. The substitution of an inert gas, nitrogen, for the carbon dioxide also resulted in a product having a base number of 10. The use of air instead of carbon dioxide resulted in a product having a base number of. slightly higher than 10 due to the carbon dioxide content of the air.

Example 11 280 grams of a mineral oil solution containing about 33 by weight of oil-soluble calcium petroleum sulfonates and having a base number of about 20 and a control ratio of about 2.5, was admixed with 19.4 grams of calcium hydroxide and 48 cc. of water, and the resulting admixture was heated to 200 F. Carbon dioxide was introduced into the admixture, with rapid stirring, at a rate of 5.6 cc./sec. for 40 minutes. The product was dried at 300 F. and then filtered. The product had a base number of 90.3, a control ratio of 5.46, and an EBR. of 196.

Example III 298 grams of a wet mineral oil solution containing about 33% by weight of calcium petroleum sulfonates (on a mineral oil-calcium petroleum sulfonate basis) and having a base number of about 20 (on a dry basis) and a control ratio of about 2.5 (on a dry basis), was admixed with 19.4 gramsof calcium hydroxide and 33.1 cc. of water. (A Wet mineral oil solution of calcium petroleum sulfonates refers to a product which has not been dried and filtered.) The resulting admixture was heated to 200 F. Carbon dioxide was introduced into the admixture, with rapid stirring, at a rate of 5.6 cc./ sec. for 20 minutes. The product was dried at 300 F. and

r then filtered. The product had a base number of 77.0, a

control ratio of 5.16 and an EBR of 168. 1

Example IV i 149 grams of a wet mineral oil solution containing about 33% by weight of calcium petroleum sulfonates having a base number of about 20 and a control ratio of about 2.5, was diluted with 140 grams of lubricatingoil distillate fraction having a viscosity of about 400 SSU at F. The base number of, the dilute solution was about 10. The dilute solution was admixed with 8.8 grams of calcium hydroxide and 14 cc. of water, and the resulting admixture was heated to 200 F. Carbon dioxide was introduced into the admixture, with rapid stirring, at a rate of 2.3 cc./sec. for 30 minutes. The product was dried at 300 F. and then filtered. The producthad a base number of 31.5, a controlcratio of 5.15 and an EBR of 167.

Example V Example VI 200 grams of the product of Example V was admixed with 17.6 grams of calcium hydroxide and 48 cc. of water and heated to 200 F. Carbon dioxide was introduced .into the admixture, with rapid stirring, at a rate of 5.6

cc./sec. for 30 minutes. The product was dried at 300 F. and then filtered. The product had a base number of 117.0.

Example VII 97 grams of the product of Example VI was admixed with 8.8 grams of calcium hydroxide and 24 cc. of water, and the resulting admixture was heated to 200 F. Carbondioxide was introduced into the admixture, with rapid stirring, at a rate of 2.3 cc./sec. for 40 minutes. The product was dried at 300 F. and then filtered. The product had a base number of 162.2, a control ratio of 7.21 and an EBR of 700.

Example VIII 140 grams of a mineral oil solution containing about 33% by weight of calcium petroleum sulfonates and having a base number of about 20 was admixed with 44 grams of calcium hydroxide and 120 cc. of water. The resulting admixture was heated to 200 F. Carbon dioxide was introduced into the admixture, with rapid stirring, at arate of 2.3 cc./sec. for 3 hours and 45 minutes. The product was dried at 300 F. and then filtered. The product had a base number of 147, a control ratio of 6.59 and an EBR of 400.

' Example IX Four kilograms of a mineral oil solution containing about 16% by weight of calcium petroleum sulfonates and having a base number of about and a control ratio of about 2.5 was admixed with 3.1% by weight, based on the oil solution of calcium petroleum sulfonates, of calcium hydroxide and 4.3 by weight, based on the oil solution of calcium petroleum sulfonates, of water. The resulting admixture was heated to 200 F. and sprayed into a closed vessel into a carbon dioxide atmosphere. The rate of introduction of carbon dioxide into the vessel was 1.8 grams/minute, the carbon dioxide dosage being 1.8% by weight based on the oil solution of calcium petroleum sulfonates. The time of carbon dioxide addition was 40 minutes. of about 5 pounds per square inch gage. The resulting product was dried and filtered. The product had a base number of 47.8.

Example X Two'kilograms of a wet mineral oil solution containing about 33% by weight of calcium petroleum sulfonates and having a base number of about and a control ratio of about 2.5 was diluted with 2 kilograms of a lubricating oil distillate fraction having a viscosity of about 100 SSU at 100 F. The base number of the dilute solution was about 10. The dilute solution was admixed with 3.1% by weight, based on the dilute oil solution of calcium petroleum sulfonates, of calcium hydroxide and Example XI 400 pounds of a mineral oil solution containing about 33% by weight of calcium petroleum sulfonates and having a base number of about 20 and a control ratio of about 2.5, was diluted with 93 by weight, based on the mineral ,oil solution of calcium petroleum sulfonates, of a lubricating oil fraction having a viscosity of about 100 SSU at 100 F. The base number of the diluted solution was about 10.. The diluted solution was admixed with 6.1% by weight of calcium hydroxide and 16.4% by weight of .water, both percentages being based on the mineral oilcalcium petroleum sulfonate starting material. The resulting admixture was heated to 200 F., and 3.1% by weight, based on the starting material, of carbon dioxide was added thereto with agitation. The resulting product The reaction was carried out under a pressure The resulting admixture was dried and filtered. The product had a base number of 42.4.

Example XII 400 pounds of a wet mineral oil solution containing about 3% by weight of calcium petroleum sulfonates and having a base number of about 20 and a control ratio of about 2.,5 was diluted with by weight, based on the mineral oil solution of calcium petroleum sulfonates, of a lubricating oil fraction having a viscosity of about SSU at 100 F. The base number of the diluted solution was about 11. The diluted solution was admixed with 10.4% by weight of calcium hydroxide and 21.7% by weight of water both percentages being based on the mineral oil-calcium petroleum sulfonate starting material. The resulting admixture was heated to 200 F., and 3.9% by weight, based on the starting material, of carbon dioxide was added thereto with agitation. The resulting product was dried and filtered. The product had a base number of 56.

Example XIII grams of a mineral oil solution containing about 27% by weight of neutral barium petroleum sulfonates having a sulfate ash of 6.95% w., was diluted with 140 grams of a lubricating oil fraction having a viscosity of about 400 SSU at 100 F. The dilute solution was admixed with 36 grams of barium hydroxide and 32 cc. of water, and the resulting admixture was heated to F. Carbon dioxide was introduced into the admixture, with rapid stirring, at a rate of 5.6 cc./sec. for 2 hours. The product was dried at 300 F. and then filtered. The product had a base number of 44.7, a sulfate ash content of 13.3% w., a control ratio of 3.36 and an EBR of 232.

Example XIV 77 grams of a mineral oil solution containing about 60% by weight of sodium petroleum sulfonates wa diluted with 63 grams of a lubricating oil fraction having a viscosity of about 100 SSU at 100 F. and with 70 grams of a lubricating oil fraction having a viscosity of about 400 SSU at 100 F. The resulting solution was admixed with 17.6 grams of calcium hydroxide, 7.1 grams of calcium chloride and 48 cc. of water, and the resulting admixture was heated to 200 F. Carbon dioxide was introduced into the admixture, with rapid stirring, at a rate of 5.6 cc./sec. for 2 hours. The product was dried at 300 F. and then filtered. The resulting mineral oil solution of basic calcium petroleum sulfonates had a base number of 46.25, a sulfate ash con tent of 10.2% w., a control ratio of 4.53 and an EBR of 122.

Example XV 280 grams of a mineral oil solution containing about 14% by weight of calcium C c -alkyl salicylates, the solution having a base number of 28.5 and a sulfate ash content of 3.90% w., was admixed with 8.8 grams of calcium hydroxide and 24 cc. of water. The resulting admixture was heated to 200 F. Carbon dioxide was introduced into the admixture, with rapid stirring, at a rate of 5.6 cc./sec. for 2 hours and 45 minutes. The resulting product was dried at 300 F. and then filtered. The product had a base number of 58.4 and a sulfate ash content'of 7.62% w.

in the process of the present invention, it is necessary that the basification agent, that is, the polyvalent metal salt of a weak inorganic acid, be formed in situ. It has been found that a highly basic product cannot be obtained by the use of the preformed polyvalent metal salt, as indicated by the following examples:

Example XVI 140 grams of a mineral oil solution containing about 33% by weight of calcium petroleum sulfonates and having a base number of about 20 was diluted with 140 grams Example XVII 140 grams of a mineral oil solution containing about 33% by weight of calcium petroleum sulfonates and having a base number of about 20, was diluted with 140 grams of a lubricating oil fraction having a viscosity 'of about 400 SSU at 100 F. The base number of the resulting dilute solution was about 10. Five cc. of water was added to the resulting dilute solution, and carbon dioxide was introduced thereinto, with rapid stirring, at a very high rate for 20 minutes at 190 F. Then 11.9 grams of calcium carbonate in 10 cc. of water was added to the resulting mixture, and stirring was continued for 1 hour at 190 F. The resulting product was dried at 300 F. and then filtered. The product had a base number of 10. r r

It will be noted that, in the above Examples XVI and XVlI, no increase in basicity was obtained byusing a preformed calcium carbonate instead of calcium carbonate formed in situ, as by the reaction of calcium hydroxide and carbon dioxide, in accordance with the present process.

Ithas also beenfound that the presence of water is necessary to incorporate basicity into the oil-soluble organic acid compound starting material. The amount of water present in the reaction mixture should be at least about 2% by weight, and preferably at least about 5% by weight, based on the organic acid compound starting material. The following example illustrates the fact that virtually no increase in basicity of the starting material can be obtained in the absence of water.

Example XVIII A mineral oil solution containing about 16% by weight of calcium petroleum sultonates and having a base number of about 10, was admixed with 3.1% by weight, based on the oil solution of calcium petroleum sulfonates, of calcium hydroxide, and the resulting admixture was heated to 200 F. Carbon dioxide was introduced into the admixture, Withrapid stirring, at a rate of 1 gram/ minute, the carbon dioxide dosage being 1.3% by weight, based on oil solution of calcium petroleum sulfonates. The resulting product was dried at 300 F. and then filtered. The product had a base number of 11.0. Thus the basicity of the starting material was increased by only about one unit.

Example XIX 1000 grams of a mineral oilsolution containing 23% by weight of the sodium salts of petroleum naphthenic acids having a molecular weight rangeof about 400 to 450 was thoroughly mixed, at a temperature of ISO-200 F. for 1 hour, with 150 grams of 77% by weight of calcium chloride and with'2 50 milliliters of water. The oil phase was then separated from the aqueous phase, and again treated with an identical CaCl H O mixture inan identical manner. The resulting oil phase was separated from the resulting aqueous phase and Washedthoroughly at a temperature of l80--200 F. with 100 milliliters of Water containing 1 gram of calcium hydroxide. phase was separated from the aqueous phase, dried at 300 F and filtered. The product was the neutral calcium salt of the petroleum naphthenic acids; it had a sulfated residue of 3.3% and a base number of 26.8.

The oil 1003 grams of this product were mixed with 501 grams of a high viscosity index lubricating oil fraction having mixture, whereby a mineral oil solution of barium 10 a viscosity of about 100 SSU (Seconds SayboltUnivetsal) at 100 F., 144 grams of calcium hydroxide and 234 milliliters of water. This mixture was heated to 200 F. and stirred continuously. Carbon dioxide was bubbled into the mixture at the rate of 0.7 gram per minute for minutes. The mixture was then dried at 300 F. and filtered. The product was an oil solution of the highly basic calcium salt of the naphthenic acids; it had a base number of 59.1, a sulfated ash of 7.18% and an EBR of 230.

Example XX 58.3 pounds of the mineral oil solution of sodium sulfonates described in Example XIX were mixed with 29.2 pounds of a high viscosity index lubricating oil fraction having a viscosity of about SSU at 100 F. It was treated, consecutively, in the manner described in Example XIX, with two mixtures of calcium chloride in water. Each of these mixtures was made up from 8.7 pounds of 77% by weight calcium chloride and 14.6 pounds of water. Following these treatments, the separated oil phase was washed thoroughly at 180-200 F. with 5.8 pounds of water containing 51 grams of calcium hydroxide. The oil phase was then separated from the aqueous phase to give an oil solution of neutral calcium naphthenates. 43.7 pounds of the product was then mixed with 8.4 pounds of calcium hydrmoxide and 11.4 pounds of water and the mixture heated to 200 F. While the mixture was continuously stirred, 4.2 pounds of carbon dioxide were bubbled into the mixture over a period of 225 minutes. The mixture was then dried at 300 F. and filtered to give an oil solution of highly basic calcium naphthenates as product. The product had a base number of 66.6, a sulfated residue of 8.08% and an EBR of 262.

The highly basic products in accordancewith the present invention are particularly useful as addition agents for lubricating oils.

Although the process of the present invention has been described in. detail with respect to the preparation of highly basic alkaline earth metal salts of oil-soluble organic acids, it is also applicable to the preparation of organic acid salts of other polyvalent metals, such as of zinc, lead, copper, tin, aluminum, and the like.

This application is a continuation in part of our copending application Serial No. 358,956,. filed June 1, 1953, and now abandoned. r

We claim as our invention:

1. A method for increasing the basicity of a mineral oil solution of calcium petroleum sulfonates which comprises admixing said mineral oil solution containing at least 10% by Weight of calcium, petroleum sulfonates, said sulfonates being the only chemically reactive organic compounds present in said solution, with an aqueous suspension containing a substantial amount of calcium hydroxide, the weight of water in said suspension being at least equal to 2% of the weight of said mineral oil solution, and adding carbon dioxide to. the resulting admixture, whereby a mineral oil solution of calcium petroleum sulfonates of increased'basicity is obtained.

2. A method for increasing the basicity of a mineral oil solution of barium petroleum sulfonates which comprises admixing said mineral oil solution containing at least 10% by weight of barium petroleum sulfonates, said sulfonates being the only chemically reactive organic compounds present in said solution, with an aqueous suspension containing a substantial amount of barium hydroxide, the weight of water in said suspension being at least equal to 2% of the weight of saidmineral oil solution, and adding carbon dioxide to the resulting adpetroleum sulfonates of increased basicity is obtained.

3. A method for preparing a mineral oil solution of oil-soluble, highlybasic calcium petroleum sulfonates which comprises admixing. a mineral oil solution containing at least 10% by weight of sodium petroleum sulfonates, said sulfonates being the only chemically reactive organic compounds present in said solution, with an amount of calcium chloride sufficient to convert said sodium petroleum sulfonates to neutral calcium petroleum sulfonates, a substantial amount of calcium hydroxide and a weight of water equal to at least 2% of the weight of such mineral oil solution, and adding carbon dioxide to the resulting admixture, whereby a mineral oil solution of oil-soluble, highly basic calcium petroleum sulfonates is obtained.

4. A method for increasing the basicity of a mineral oil solution of calcium alkyl salicylates in which the alkyl group contains at least 12 carbon atoms which comprises admixing said mineral oil solution containing at least by weight of calcium alkyl salicylates, said salicylates be ing the only chemically reactive organic compounds present in said solution, with an aqueous suspension containing a substantial amount of calcium hydroxide, the weight of water in said suspension being at least equal to 2% of the weight of said mineral oil solution, and adding carbon dioxide to the resulting admixture, whereby a mineral oil solution of calcium alkyl salicylates of increased basicity is obtained.

5. A method for increasing the basicity of a mineral oil solution of alkaline earth metal petroleum sulfonates which comprises admixing said mineral oil solution containing at least 10% by weight of alkaline earth metal petroleum sulfonates, said sulfonates being the only chemically reactive organic compounds present in said solution, with a weight of water equal to at least 2% of the weight of such mineral oil solution and with a substantial amount of an alkaline earth metal base, and adding carbon dioxide to the resulting admixture, whereby a mineral oil solution of alkaline earth metal petroleum sulfonates of increased basicity is obtained.

6. A method for preparing a mineral oil solution of oil-soluble, highly basic alkaline earth metal petroleum sulfonates which comprises admixing a mineral oil solution containing at least 10% by weight of alkali metal petroleum sulfonates, said sulfonates being the only chemically reactive organic compounds present in said solution, with an amount of a water-soluble alkaline earth metal salt sufiicient to convert said alkali metal petroleum sulfonates to neutral alkaline earth metal petroleum sulfonates, a substantial amount of an alkaline earth metal base and a weight of water equal to at least 2% of the weight of such mineral oil solution, and adding carbon dioxide to the resulting admixture, whereby a mineral oil solution of oil-soluble, highly basic alkaline earth petroleum sulfonates is obtained.

7. In a method for preparing an oil-soluble, highly basic alkaline earth metal petroleum sulfonate, the steps comprising mixing an oil-soluble petroleum sulfonic acid compound, as the only reactive organic compound, with a weight of water equal to at least 2% of the weight of such sulfonic acid compound and with a substantial amount of an alkaline earth metal base, and adding carbon dioxide to the resulting mixture.

8. In a method for preparing an oil-soluble, highly basic polyvalent metal petroleum sulfonate, the steps comprising mixing an oil-soluble petroleum sulfonic acid compound, as the only reactive organic compound, with a weight of water equal to at least 2% of the weight of such sulfonic acid compound and with a substantial amount of a polyvalent metal base, and adding carbon dioxide to the resulting mixture. 7

9. In a method for preparing anoil-soluble, highly basic polyvalent metal salt of a petroleum sulfonic acid, the step comprising reacting an oil-soluble petroleum sulfonic acid compound, as the only reactive organic compound, in the presence of a weight of water equal to at least 2% of the weight of said sulfonic acid compound, with a polyvalent metal carbonate which is formed in situ by the reaction of a polyvalent metal base and carbon dioxide, at least a portion of said polyvalent metal base being in the free state.

10. In amethod for preparing an oil-soluble, highly basic alkaline earth metal alkyl salicylate in which the alkyl radical contains at least 12 carbon atoms, the steps comprising mixing an oil-soluble alkyl salicylic acid compound in which the alkyl radical contains at least 12 carbon atoms, as the only reactive organic compound, with a weight of water equal to at least 2% of the weight of such salicylic acid compound and with a substantial amount of an alkaline earth metal base, and adding carbon dioxide to the resulting mixture.

11. In a method for preparing an oil-soluble, highly basic polyvalent metal salt of an alkyl salicylic acid in which the alkyl radical contains at least 12 carbon atoms, the steps comprising mixing an oil-soluble alkyl salicylic acid compound in which the alkyl radical contains at least 12 carbon atoms, as the only reactive organic compound, with a weight of water equal to at least 2% of the weight of such salicylic acid compound and with a substantial amount of a polyvalent metal base, and adding carbon dioxide to the resulting mixture.

12. In a method for preparing an oil-soluble, highly basic polyvalent metal salt of an alkyl salicylic acid, the step comprising reacting an oil-soluble alkyl salicylic acid compound in which the alkyl group contains at least 12 carbon atoms, as the only reactive organic compound, in the presence of a weight of water equal to at least 2% of the weight of said salicylic acid compound, with a polyvalent metal carbonate which is formed in situ by the reaction of a polyvalent metal base and carbon dioxide, at least a portion of said polyvalent metal base being in the free state.

13. In a method for preparing an oil-soluble, highly basic polyvalent metal salt of a petroleum naphthenic acid, the step comprising reacting an oil-soluble petroleum naphthenic acid compound, as the only reactive organic compound, in the presence of a weight of water equal to at least 2% of the weight of said naphthenic acid compound, with a polyvalent metal carbonate which is formed in situ by the reaction of a polyvalent metal base and carbon dioxide, at least a portion of said polyvalent metal base being in the free state.

14. In a method for preparing oil-soluble, highly basic alkaline earth metal petroleum naphthenates, the steps comprising mixing an oil-soluble petroleum naphthenic acid compound, as the only reactive organic compound, with a weight of water equal to at least 2% of the weight of such naphtheni'c acid compound and with a substantial amount of an alkaline earth metal base, and adding carbon dioxide to the resulting mixture.

15. A method for increasing the basicity of a mineral oil solution of alkaline earth metal petroleum naphthenates which comprises admixing said mineral oil solution containing at least 10% by Weight of alkaline earth metal petroleum naphthenates, said naphthenates being the only chemically reactive organic compounds present in said solution, with a weight of water equal to at least 2% of the weight of such mineral oil solution and with a substantial amount of an alkaline earth metal base, and adding carbon dioxide to the resulting admixture, whereby a mineral oil solution of alkaline earth metal petroleum naphthenates of increased basicity is obtained.

16. In a method for preparing an oil-soluble polyvalent metal salt of an organic acid, the step comprising reacting, as the only chemically reactive organic material, an oil-soluble organic acid compound containing at least 12 carbon atoms and selected from the class consisting of (1) the petroleum sulfonic acids, (2) carbocyclic carboxylic acids and (3) salts of these acids with alkali metals and with alkaline earth metals, in the presence of a substantial aqueous phase comprising a weight of water equal to not less than 2% of the weight of said organic acid compound, with apolyvalent metal carbonate which is formed in situ by the reaction of a polyvalent metal base and carbon dioxide, at least a part of said polyvalent metal base being in the free state.

17. In a method for preparing an oil-soluble polyvalent metal salt of an organic acid, the step comprising reacting a hydrocarbon oil solution containing as the only chemically reactive organic material, at least 10% by weight of an oil-soluble organic acid compound containing at least 12 carbon atoms and selected from the class consisting of (1) petroleum sulfonic acids, (2) carbocyclic carboxylic acids and (3) salts of these acids with alkali metals and with alkaline earth metals, in the presence of a substantial aqueous phase comprising a Weight of Water equal to not less than 2% of the weight of said oil solution, with a polyvalent metal carbonate which is formed in situ by the reaction of a polyvalent metal base and carbon dioxide, at least a part of said polyvalent metal base being in the free state.

18. In a method for preparing an oil-soluble polyvalent metal salt of an organic acid, the step comprising mixing a hydrocarbon oil solution containing as the only chemically reactive organic material at least 10% by weight of an oil-soluble organic acid compound containing at least 12 carbon atoms per molecule and selected from the class consisting of (l) petroleum sulfonic acids, (2) carbocyclic carboxylic acids and (3) salts of these acids with alkali metals and with alkaline earth metals with a 14 weight of water equal to at least 2% of the weight of said oil solution, and a substantial amount of a polyvalent metal base, and adding carbon dioxide to the resulting mixture, said aqueous phase being maintained throughout the addition of carbon dioxide.

19. In a method for preparing an oil-soluble alkaline earth metal salt of an organic acid, the step comprising mixing a hydrocarbon oil solution containing as the only chemically reactive organic material at least 16% by Weight of an oil-soluble organic acid compound containing at least 12 carbon atoms per molecule and selected from the class consisting of (l) petroleum sulfonic acids, (2) carbocyclic carboxylic acids and (3) salts of these acids with alkali metals and with alkaline earth metals with a weight of Water equal to at least 2% of the Weight of said oil solution, and a substantial amount of an alkaline earth metal base, and adding carbon dioxide to the resulting mixture, said aqueous phase being maintained throughout the addition of carbon dioxide.

References Cited in the file of this patent UNITED STATES PATENTS 2,501,732 Mertes Mar. 28, 1950 2,616,924 Assell et al Nov. 4, 1952 2,619,460 Neff Nov. 25, 1952 2,695,910 Asseff et al Nov. 20, 1954 

16. IN A METHOD FOR PREPARING AN OIL-SOLUBLE POLYVALENT METAL SALT OF AN ORGANIC ACID, THE STEP COMPRISING REACTING, AS THE ONLY CHEMICALLY REACTIVE ORGANIC MATERIAL, AN OIL-SOLUBLE ORGANIC ACID COMPOUND CONTAINING AT LEAST 12 CARBON ATOMS AND SELECTED FROM THE CLASS CONSISTING OF (1) THE PETROLEUM SULFONIC ACIDS, (2) CARBOCYCLIC CARBOXYLIC ACIDS AND (3) SALTS OF THESE ACIDS WITH ALKALI METALS AND WITH ALKALINE EARTH METALS, IN THE PRESENCE OF A SUBSTANTIAL AQUEOUS PHASE COMPRISING A WEIGHT OF WATER EQUAL TO NOT LESS THAN 2% OF THE WEIGHT OF SAID ORGANIC ACID COMPOUND, WITH A POLYVALENT METAL CARBONATE WHICH IS FORMED IN SITU BY THE REACTION OF A POLYVALENT METAL BASE AND CARBON DIOXIDE, AT LEAST A PART OF SAID POLYVALENT METAL BASE BEING IN THE FREE STATE. 